This invention relates generally to door and window casings for framing openings in the walls of buildings to receive doors and windows. More specifically, the invention relates to an improved jamb assembly for such casings wherein elements of the jamb assembly, including the stop, brickmold, width extensions where applicable, and bottom portions of the side jamb members are formed from substantially solid extruded thermoplastic material.
In constructing a building such as a house, it is common that openings for receiving doors are first roughly framed in with wall studs, which usually are made of wood. Subsequently, the rough framed openings are finished with a wooden door casing, which often is provided with a decorative exterior brickmold that abuts the brick or siding on the outside of the building. The door casing is formed from a pair of spaced vertical side jambs connected at their upper ends with a horizontal head jamb. A sill usually extends between the lower ends of the side jambs. In some instances, the brickmold of the casing is milled as an integral part of the jambs and in other instances the brickmold is nailed or stapled to the jambs along their outside edges. A stop usually is milled into the jambs and the stop extends around the inside peripheral face of the casing. In use, a closed door mounted in the casing rests against the stop. In many instances, the stop bears a weather strip that seals against the closed door to prevent drafts.
In sidelight door casings, a pair of spaced vertical mullions or mull posts extend between the sill and the head jamb to form a central opening for receiving a hinged door and a pair of narrow side openings on either side of the central opening for receiving sidelight windows. Mull posts typically are formed of a pair of back-to-back wooden supports that have been milled along their exposed faces to provide stops for abutting a closed door or receiving and securing the sidelight windows. A strip of decorative molding is commonly nailed along the outside edges of the supports to cover there outside edges, to cover the junction between the supports, and to lend a pleasing appearance to the finished casing.
A traditional method of fabricating door jambs is to mill the jambs from larger pieces of a high quality clear wood. In this process, a relatively thick piece of wood for each jamb of the casing is passed through a milling machine and unwanted portions are cut or milled away and discarded as sawdust. The milling process produces the raised stops and other structural features of the jambs. Obviously, this process is wasteful and is becoming more expensive in light of the ever-increasing cost of lumber. In some instances, the entire cross-section of each jamb, including the brickmold, is milled from a single length of thick lumber. In other instances, the jambs are milled from two or more pieces of wood to form the frame and stop and a separate decorative brickmold. The brickmold is then nailed to the frame and stop to form the finished jamb profile. In either case, significant amounts of expensive lumber are required as is time consuming, expensive, and wasteful machining steps.
In the past few years, dwellings with thicker outside walls have become popular because thicker walls accommodate more insulation and thus provide higher R-values. The use of thicker walls has given rise to a requirement for correspondingly thicker door casings that span the width of the wider walls. For casing made from wooden jambs, this has meant the use of even wider boards to fabricate the jambs with the wider boards being milled to produce the stops and perhaps the brickmold of the casing. Typically, this is an even more wasteful process than milling jambs for traditional narrower casings since more wood is used and, in many instances, more wood is milled away.
All of this adds to the final cost of traditional door casings. Further, and perhaps even more pertinent, the exposed wooden brickmold and the exposed portions of molding along the mull posts of side light casings require periodic painting and maintenance in order to prevent rotting as a result of exposure to the weather. Even with the most careful maintenance, these exposed wooden portions of can, over time, begin to rot from within, whereupon the entire door casing usually must be replaced. Rot due to moisture can be a particular problem at the bottom ends of the side jambs where they meet and are secured to a doorsill. Rain water that runs down onto the door sill tends to be wicked into the bottoms of the side jambs causing rot.
Casings have been developed that are wholly or partially comprised of extruded thermoplastic portions. For example, U.S. Pat. No. 4,430,830 to Sailor teaches a casing for mounting a window or door in an opening of an existing structure. The casing is made of jambs that include an extruded plastic or metal outer frame forming the stop and a wooden inner frame to which the outer frame is attached. Fasteners such as screws are provided for attaching the outer frame to the rough framed opening and a molded decorative cover is provided for concealing the fastners, in Sailor, the portion of the outer frame forming the stop and brickmold are hollow and thus provide little enhanced strength or rigidity to the frame. Further, the hollow brickmold makes it unsuitable for receiving standards nails for securing the casing to the building. Non-carpentry standard installation techniques are thus required, which is distasteful to many carpenters. In addition, the casing of Sailor requires the use of an auxillary cover to conceal the fastners attaching the frame to the building structure.
U.S. Pat. No. 5,058,323 to Gerritsen teaches a casing wherein a plastic member wraps around a wooden jamb with a milled stop or that wraps around a wooden jamb and provides its own plastic stop. An attachable brickmold is also included. This casing, like that of Sail or, has flimsy hollow portions unsuitable for holding nails and liable to be punctured or otherwise deformed by heavy use or forcible contact. U.S. Pat. No. 5,182,880 to Berge, Jr., et al., teaches a cladded jamb similar to that taught by Gerritsen in that it wraps around a traditional wooden jamb and stop. Thus, a fully milled wooden jamb is still required.
U.S. Pat. No. 5,661,943 of Hagel discloses a milled wooden door casing wherein the bottom sections of the side jambs are formed from a composite material made of wood particulate that is mixed with resins. These bottom sections are milled or otherwise formed to have the same profile as the wooden portions of the jambs and are joined to the wooden portions with finger joints. A goal of this jamb structure is to address the problem of rot and decay at the bottoms of the sides jambs where the side jambs meet the sill. While the Hagel frame is an improvement in this regard over traditional all wooden jambs, it nevertheless has its own inherent problems and shortcomings. For example, The finger joint that joins the composite bottom sections to the side jambs tends to be relatively weak and can be broken off, especially prior to the attachment of brickmold after installation of the casing. In addition, the side jambs and head jamb must still be milled to define their finished profile after the composite bottom sections are joined. Obviously, this does not address the problems of waste and expense.
Briefly described, the present invention, in a preferred embodiment thereof, comprises an improved door jamb assembly for constructing a door casing. The jamb assembly comprises a frame member preferably formed of a relatively flat wooden board having inside and outside faces and inside and outside edges. A substantially solid extruded plastic brickmold and stop member is mounted to the frame member and is profiled to define the raised stop and brickmold of the assembly. The wooden frame member provides a traditional wooden surface and provides a solid structure for receiving nails and screws when mounting the casing and hanging a door from a side jamb thereof. The brickmold and stop member can be extruded as a single unitary piece, which is preferred in some cases or can be extruded as separate pieces joined with fasteners or adhesive.
The brickmold and stop member in the preferred embodiment is profiled to define a leg that at least partially overlies the inside face of the frame member to which it is attached and that defines a raised stop relative to the inside face for abutting a closed door. The brickmold and stop member is also profiled to define a decorative brickmold that frames the casing on the outside of a building in which the casing is installed. The extruded brickmold and stop member is adhered or otherwise firmly mounted to the wooden frame member so that together they form a traditional profiled door jamb.
The brickmold and stop member is co-extruded from a thermoplastic material and preferably has a relatively less dense blown thermoplastic core covered by a relatively more dense plastic outer skin or covering. The density of the blown core is sufficient to receive and hold a traditional finishing nail so that the assembly can be nailed in place through the brickmold in the traditional way. In one embodiment, the brickmold is co-extruded with a relatively hard plastic flange or tab that projects outwardly from the assembly and that is positioned to overlie the outside surface of a building around the rough door opening. During installation, the casing is positioned in the opening with its flanges disposed against the outer wall of the building, whereupon the flanges are fastened with nails or screws. Brick, lap board, or another exterior finish can then be applied over the flanges abutting the brickmold to result in a traditional looking exterior door casing. Preferably the stop is extruded with a groove or slot that extends along the stop adjacent the inside face of the frame member for receiving and holding the mounting tab of a length of weather stripping.
In another embodiment of this invention, the decorative brickmold has an exposed outer surface and an inner surface that is formed to define a recess. A stabilizer, such as a strip of wood, is disposed in the recess for stabilizing the brickmold and for providing a more secure medium through which attaching nails can extend. A short tab is co-extruded with the brickmold and stop member and the tab extends partially over the outside face of the wooden frame member. Staples can be driven through the tab and into the wooden frame member to attach the brickmold and stop member firmly and securely to the frame member. In one embodiment, the inside face of the wooden frame member is milled with a recessed dado and the brickmold and stop member is provided with a projection sized to be received in the recessed dado. Staples can be driven through the projection and into the wooden frame member for attachment of the brickmold and stop member to the frame member.
In still another embodiment, the mull posts of a side light door casing are each formed from a flat back-to-back wooden frame member. A generally U-shaped extruded thermoplastic molding and stop member is secured to the frame members along the outside edges thereof. The legs of the molding and stop member overlie a portion of the exposed faces of the frame members and form elongated stops that extend along the length of the mull posts intermediate the inside and outside edges thereof. The bight portions of the molding and stop members cover the outside edges of the frame members and provide a decorative appearance to the exposed portions of the mull posts. The stop formed along one face of the mull post abuts a closed door mounted in the opening of the casing and the stop along the other face of the mull post provides a surface against which side light windows can be mounted in the casing. In one configuration, the exposed faces of the mull posts are milled with recessed dados extending along their lengths and the extruded molding and stop members are provided with projections that extend into the milled recesses to hold the molding and stop member in place on the mull posts. Nails or staples can be driven through the projections if desired and into the frame members to hold the molding and stop members in place.
In yet another embodiment, the vertical side jambs of a door casing are formed from wooden frame members having extruded plastic brickmold and stop members attached along their outside edge portions as described above. In this embodiment, however, the immediate bottom portions of the vertical frame members include an extruded thermoplastic attachment that has a relatively less dense blown plastic core covered by a relatively more dense plastic skin. Each attachment is secured to the bottom of its respective frame member with a tongue and groove joint and the extruded brickmold and stop member spans the joint between the attachment and the wooden portion of the frame member. As a result, the bottom portions of the side jambs where the jambs meet a doorsill are plastic and are thus immune to rot and decay. Further, the relatively weak joint between the wooden portion of the frame member and its plastic bottom section is strengthened and reinforced because the extruded brickmold and stop member spans the joint and is fastened both to the wooden portion of the frame member and to the plastic bottom section. As a result, the assembly is rigid and strong and not subject to being broken during installation.
An additional embodiment of the door jamb assembly is designed to form a casing that is deeper for use with thicker walls. This embodiment comprises substantially the same components as the embodiment of FIGS. 1 and 4 except that the wooden frame members are wider to span a thicker wall of, say, six inches rather then the traditional four. In order to adapt the standard extruded stop member to the wider jamb, an extruded extender is provided. The extender is adapted to abut the raised stop of the standard stop member and extend therefrom to an opposite edge, which forms a secondary raised stop relative to the face of the frame member. In this way, the standard extruded stop member is extended and a standard set of components can be used to accommodate either a standard depth or an extended depth casing.
Thus it is seen that an improved door jamb assembly is now provided wherein the need to mill or otherwise machine the stops, molding, and other portions of the jamb is eliminated. A relatively inexpensive flat board forms the frame of the assembly. The stop members and the decorative molding portions of the jamb assembly are formed from thermoplastic co-extrusions that look, feel, and hold nails like wood but that require substantially less maintenance than wood and are not subject to rot or deterioration as is wood. The jamb assembly is used to fabricate a door casing that can be installed with finish nails in the same way as a traditional wooden casing. This is an advantage to carpenters, who prefer traditional installation methods to new or complex alternate methods. As an added advantage, the bottom sections of the side jambs that meet and are attached to a doorsill are formed of extruded plastic material that is immune to rot and deterioration. Finally, a standardized extruded extension is provided to adapt the standard width stop member to a deeper casing for use with thicker walls. These and many other objects, features, and advantages will become more apparent upon review of the detailed description set forth below taken in conjunction with the accompanying drawings, which are briefly described as follows.